Graphene is a single atomic plane of graphite. Whilst it is the thinnest and strongest material available, it is generally not used in this isolated state, but rather is more commonly incorporated as a composite (laminate) comprising a substrate supporting the attached graphene. The graphene may be a monolayer, a bilayer or a multilayer of graphene. Generally to fabricate high quality, single crystalline graphene, a high temperature deposition from vapour is required, which uses metallic substrates such as copper or nickel
Currently such a composite (laminate) is made by forming the graphene on a copper foil using chemical vapour deposition, applying a target substrate to the graphene and then removing the copper foil by using an etching bath.—This process is limiting since the etch solution is often a highly oxidising solution such as hydrofluoric acid (HF), which only a small number of substrates are resistant to. The composite (laminate) of graphene, comprising the target substrate and graphene, can then be used to transfer the graphene. If required, the target substrate may then be dissolved to leave only the graphene—.